Sierra Acai Company
Sierra Acai Company
Open 7 Days a Week
MonaVie Independent Distributor
Distributor Training
Shop Online
Enroll Now
Buy Wholesale and maintain an Active status for 2 months and we will refund your $39 Distributor Fee
Friends
Buy Wholesale and maintain an Active status for 2 months and we will refund your $39 Distributor Fee
14-September-2008 18:38:44 - Chloroplast The inside of a chloroplast The inside of a chloroplast Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. Chloroplasts absorb light and use it in conjunction with water and carbon dioxide to produce sugars, the raw material for energy and biomass production in all green plants and the animals that depend on them, directly or indirectly, for food. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH through a complex set of processes called photosynthesis. It is derived from the Greek words chloros which means green and plast which means form or entity. Chloroplasts are members of a class of organelles known as plastids. Contents 1 Evolutionary origin 2 Structure 3 Transplastomic plants 4 See also 5 References 6 External links Evolutionary origin Plant cells with visible chloroplasts. Plant cells with visible chloroplasts. Chloroplasts are one of the many different types of organelles in the plant cell. They are generally considered to have originated as endosymbiotic cyanobacteria i.e. blue-green algae. This was first suggested by Mereschkowsky in 1905 1 after an observation by Schimper in 1883 that chloroplasts closely resemble cyanobacteria. 2 All eukaryote chloroplasts are thought to derive directly or indirectly from a single endosymbiotic event in the Archaeplastida, except for Paulinella chromatophora, which has recently acquired a photosynthetic cyanobacterial endosymbiont which is not closely related to chloroplasts of other eukaryotes.3 In that they derive from an endosymbiotic event, chloroplasts are similar to mitochondria but chloroplasts are found only in plants and protista. The chloroplast is surrounded by a double-layered composite membrane with an intermembrane space; it has its own DNA and is involved in energy metabolism. Further, it has reticulations, or many infoldings, filling the inner spaces. In green plants, chloroplasts are surrounded by two lipid-bilayer membranes. The inner membrane is now believed to correspond to the outer membrane of the ancestral cyanobacterium. Chloroplasts have their own genome, which is considerably reduced compared to that of free-living cyanobacteria, but the parts that are still present show clear similarities with the cyanobacterial genome. Plastids may contain 60-100 genes whereas cyanobacteria often contain more than 1500 genes.4 Many of the missing genes are encoded in the nuclear genome of the host. The transfer of nuclear information has been estimated in tobacco plants at one gene for every 16000 pollen grains.5 In some algae such as the heterokonts and other protists such as Euglenozoa and Cercozoa, chloroplasts seem to have evolved through a secondary event of endosymbiosis, in which a eukaryotic cell engulfed a second eukaryotic cell containing chloroplasts, forming chloroplasts with three or four membrane layers. In some cases, such secondary endosymbionts may have themselves been engulfed by still other eukaryotes, thus forming tertiary endosymbionts. In the alga Chlorella, there is only one chloroplast, which is bell shaped. Structure Chloroplasts are observable morphologically as flat discs usually 2 to 10 micrometer in diameter and 1 micrometer thick. In land plants they are generally 5 μm in diameter and 2.3 μm thick. The chloroplast is contained by an envelope that consists of an inner and an outer phospholipid membrane. Between these two layers is the intermembrane space. A typical parenchyma cell contains about 10 to 100 chloroplasts. The material within the chloroplast is called the stroma, corresponding to the cytosol of the original bacterium, and contains one or more molecules of small circular DNA. It also contains ribosomes, although most of its proteins are encoded by genes contained in the host cell nucleus, with the protein products transported to the chloroplast. Chloroplast ultrastructure: 1. outer membrane 2. intermembrane space 3. inner membrane 1+2+3: envelope 4. stroma aqueous fluid 5. thylakoid lumen inside of thylakoid 6. thylakoid membrane 7. granum stack of thylakoids 8. thylakoid lamella 9. starch 10. ribosome 11. plastidial DNA 12. plastoglobule drop of lipids Chloroplast ultrastructure: 1. outer membrane 2. intermembrane space 3. inner membrane 1+2+3: envelope 4. stroma aqueous fluid 5. thylakoid lumen inside of thylakoid 6. thylakoid membrane 7. granum stack of thylakoids 8. thylakoid lamella 9. starch 10. ribosome 11. plastidial DNA 12. plastoglobule drop of lipids Within the stroma are stacks of thylakoids, the sub-organelles which are the site of photosynthesis. The thylakoids are arranged in stacks called grana singular: granum. A thylakoid has a flattened disk shape. Inside it is an empty area called the thylakoid space or lumen. Photosynthesis takes place on the thylakoid membrane; as in mitochondrial oxidative phosphorylation, it involves the coupling of cross-membrane fluxes with biosynthesis via the dissipation of a proton electrochemical gradient. In the electron microscope, thylakoid membranes appear as alternating light-and-dark bands, each 0.01 μm thick. Embedded in the thylakoid membrane is the antenna complex, which consists of the light-absorbing pigments, including chlorophyll and carotenoids, and proteins which bind the chlorophyll. This complex both increases the surface area for light capture, and allows capture of photons with a wider range of wavelengths. The energy of the incident photons is absorbed by the pigments and funneled to the reaction centre of this complex through resonance energy transfer. Two chlorophyll molecules are then ionised, producing an excited electron which then passes onto the photochemical reaction centre. Recent studies have shown that chloroplasts can be interconnected by tubular bridges called stromules, formed as extensions of their outer membranes.67 Chloroplasts appear to be able to exchange proteins via stromules,8 and thus function as a network. Transplastomic plants Recently, chloroplasts have caught attention by developers of genetically modified plants. In most flowering plants, chloroplasts are not inherited from the male parent,910 although in plants such as pines, chloroplasts are inherited from males.11 Where chloroplasts are inherited only from the female, transgenes in these plastids cannot be disseminated by pollen. This makes plastid transformation a valuable tool for the creation and cultivation of genetically modified plants that are biologically contained, thus posing significantly lower environmental risks. This biological containment strategy is therefore suitable for establishing the coexistence of conventional and organic agriculture. The reliability of this mechanism has not yet been studied for all relevant crop species. However, the research programme Co-Extra recently published results for tobacco plants, demonstrating that the containment of transplastomic plants is highly reliable with a tiny failure rate of 3 in 1,000,000.10 See also Chloroplast membrane Inner membrane Outer membrane Calvin cycle Light-dependent reaction References This article contains material from the Science Primer published by the NCBI, which, as a U.S. government publication, is in the public domain. ^ Mereschkowsky C 1905. Ãœber Natur und Ursprung der Chromatophoren im Pflanzenreiche. Biol Centralbl 25: 593-604. ^ Schimper AFW 1883. Ãœber die Entwicklung der Chlorophyllkörner und Farbkörper. Bot. Zeitung 41: 105-14, 121-31, 137-46, 153-62. ^ Patrick J. Keeling 2004. Diversity and evolutionary history of plastids and their hosts. American Journal of Botany 91: 1481-1493. doi:10.3732/ajb.91.10.1481. ^ Martin W, Rujan T, Richly E, Hansen A, Cornelson S, Lins T, Leister D, Stoebe B, Hasegawa M, Penny D 2002. Evolutionary analysis of Arabidopsis, cyanobacterial, and chloroplast genomes reveals plastid phylogeny and thousands of cyanobacterial genes in the nucleus. Proc Natl Acad Sci 99: 12246-12251. doi:10.1073/pnas.182432999. PMID 12218172. ^ Huang CY, Ayliffe MA, Timmis JN 2003 Mar 6. Direct measurement of the transfer rate of chloroplast DNA into the nucleus. Nature 422 6927: 72-6. doi:10.1038/nature01435. ^ Köhler RH Hanson MR 2000 Plastid tubules of higher plants are tissue-specific and developmentally regulated. Journal of Cell Science 113, 81-89 ^ Gray JC, Sullivan JA, Hibberd JM Hansen MR 2001 Stromules: mobile protrusions and interconnections between plastids. Plant Biology 3, 223-233 ^ Köhler RH, Cao J, Zipfel WR, Webb WW Hanson MR 1997 Exchange of protein molecules through connections between higher plant plastids. Science 276, 1039-1042 ^ Stegemann, S; Hartmann, S; Ruf, S; Bock, R Jul 2003. High-frequency gene transfer from the chloroplast genome to the nucleus Free full text. Proceedings of the National Academy of Sciences of the United States of America 100 15: 8828-33. doi:10.1073/pnas.1430924100. PMID 12817081. PMC:166398. most angiosperm species inherit their chloroplasts maternally ^ a b Ruf S, Karcher D, Bock R 2007 Apr 24. Determining the transgene containment level provided by chloroplast transformation. PNAS 104 17: 6998-7002. doi:10.1073/pnas.0700008104. PMID 17420459. ^ Powell, W. 1995 August 15. Polymorphic Simple Sequence Repeat Regions in Chloroplast Genomes: Applications to the Population Genetics of Pines. Proc Natl Acad Sci U S A. 92 17: 7759-7763. doi:10.1073/pnas.92.17.7759. PMID 7644491. In the pines, the chloroplast genome is transmitted through pollen External links Chloroplasts and Photosynthesis: The Role of Light from Kimball's Biology Pages Chloroplast, Botany Use of chloroplast DNA in studying plant phylogeny and evolution 3D structures of proteins associated with thylakoid membrane Co-Extra research on chloroplast transformation v d e Structures of the cell Organelles cytoplasmic vesicles: Endosome - Lysosome - Phagosome - Vacuole - cytoplasmic granules Melanosome, Microbody, Glyoxysome, Peroxisome, Weibel-Palade body nucleus: Nucleolus endosymbiotic: Mitochondrion - Plastid Chloroplast other: Endoplasmic reticulum - Golgi apparatus - Parenthesome - Ribosome - Vault Cytoskeleton Centrosome Centriole - Myofibril External Cell wall - Cell membrane - Cilium/Flagellum - Acrosome Other Cytoplasm v d e Botany Subdisciplines of botany Ethnobotany · Paleobotany · Plant anatomy · Plant ecology · Plant evo-devo · Plant morphology · Plant physiology Plants Evolutionary history of plants · Algae · Bryophyte · Pteridophyte · Gymnosperm · Angiosperm Plant parts Flower · Fruit · Leaf · Meristem · Root · Stem · Stoma · Vascular tissue · Wood Plant cells Cell wall · Chlorophyll · Chloroplast · Photosynthesis · Plant hormone · Plastid · Transpiration Plant life cycles Gametophyte · Plant sexuality · Pollen · Pollination · Seed · Spore · Sporophyte Plant taxonomy Botanical name · Botanical nomenclature · Herbarium · IAPT · ICBN · Species Plantarum Category · Portal Retrieved from http://en..org/wiki/Chloroplast Categories: Organelles | Photosynthesis Views Article Discussion this page History Personal tools Log in / create account Navigation Main page Contents Featured content Current events Random article Search Go Search Interaction Community portal Recent changes Contact Donate to Help Toolbox What links here Related changes Upload file Special pages Printable version Permanent link Cite this page Languages العربية বাংলা БългарÑ?ки Català Česky Dansk Deutsch Eesti Ελληνικά Español Esperanto Ù?ارسی Français Galego í•œêµì–´ Hrvatski Bahasa Indonesia Ã?slenska Italiano עברית Lietuvių Magyar МакедонÑ?ки Bahasa Melayu Nederlands 日本語 ‪Norsk bokmÃ¥l‬ ‪Norsk nynorsk‬ Occitan Plattdüütsch Polski Português Română РуÑ?Ñ?кий Simple English SlovenÄ?ina SlovenÅ¡Ä?ina СрпÑ?ки / Srpski Srpskohrvatski / СрпÑ?кохрватÑ?ки Basa Sunda Suomi Svenska Tiếng Việt Türkçe УкраїнÑ?ька ä¸æ–‡ This page was last modified on 14 September 2008, at 01:53
39 Reasons to Drink Acai Juice Every Day
What is MonaVie - Watch the 8-minute video
Discovering MonaVie Video
The Power of You Video
Effects of MonaVie Active on Antioxidant Capacity in Humans
Log into your Wholesale MonaVie Account
So many of us do not eat a balanced diet, get enough sleep, have too much stress, or are impacted with toxins and pollutants. Drinking 2 ounces of MonaVie twice a day will help your body detoxify as well as build your immune system. Its the smartest thing you can do for yourself, so start today. Buying MonaVie through our company guarantees you support 7 days a week and, if you would like to share MonaVie with your family and friends we will guide you from start to finish.
1. Click on Enroll Now (30 - 55% off retail price)
2. Pay $39 for your Wholesale ID number.
3. NO minimum order required.
4. MonaVie is delivered to your door in 3 to 5 days.